Research and Development

PIP-CAT Scans of Pervious Concrete

In keeping with the Pervious In Paradise look back, we have Dr. Narayanan Neithalath Ph.D. P.E.’s presentation of pervious concrete modeling featuring one of my favorite parts- a clip of a pervious cylinder in a CAT scan!

Dr. Neithalath’s presentation was on his research on the effect of mix design on pore structure and infiltration performance. Currently, the state of the art is rife with trial and error which ends up, at worse, with pavement failures, and best, an inconsistent mix. He wants to really understand how different aspects of the pervious concrete mix affect the different performance attributes. In this way, he wants to be able to dial in a pervious mix, with the exact attributes required for the ideal functioning of the installation.

The key feature of pervious concrete is the porosity, which we are all familiar with. Permeability is linearly related to porosity, and while that is obvious, it forms a helpful and fundamental baseline for one aspect of pervious concrete as a hardscape. Other aspects of pervious concrete are less well understood and they include types and seriousness of particle retention or clogging; oil retention, as some are considering pervious concrete as a bio-filter; strength and fracture, for structural considerations; as well as how mix design informs the size, type and structure of the voids. Dr. Neithalath is working to understand how all of these factors come together to form computational performance models for consistent designable pavements. In turn that would create a matrix of variable that could be controlled to create very precise mix designs for producers and installers.

My favorite part of Dr. Neithalath’s presentation was the video he presented of a pervious concrete cylinder in a CATscan, going all the way throughout, such that the void patterns were completely observable. Below you can see the video. I found the whole thing hypnotizing. What do you think?

To see more about Dr. Neithalath’s work, you can go to his faculty page here.

Pervious In Paradise - a summary look back

(‘View from the Hotel’ photo credit: Bob Banka)

(‘View from the Hotel’ photo credit: Bob Banka)

Pervious in Paradise was a great conference. There were great presentations, solid attendance and wonderful networking! And every night, FIREWORKS!! Well, those might have been for the SeaWorld guests, who were adjacent to the conference site, but we enjoyed it nonetheless!

As we get materials and permission, we will be posting briefs on a few of the presentations. There were some fantastic new ideas, ongoing development of existing ideas and industry knowledge getting more refined. Highlights included 

  • pervious concrete site and pavement design with Michael Hein P.E. and Chris Estes, ASLA,
  • notes from the Puget Sound with Andrew Marks P.E.,
  • some truly innovative applications of pervious concrete with Muhannad Suleiman, Ph.D.,
  • great modeling of voids and their implication with Narayanan Neithalath, Ph.D. P.E.
  • discussions of fibers and silica fume with John Kevern Ph.D. P.E. LEED AP


There were many good speakers, and solid content throughout. More soon, and we are already looking forward to the next conference! Did you go? What did you think? Your comments are always appreciated!

CSU East Bay has a new Concrete Testing Lab

CSU East Bay has a new Concrete Testing Lab

David had taken some samples at a recent pour and wanted to get them tested. Fortunately, Cristian Gaedicke, Concrete Materials Professor at CSU East Bay, had a new lab with new equipment to break in. We headed over for a tour and a testing field trip. Below are some photos of our compression testing. 

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